Results from a four-year study on the prevalence of nosocomial infections in Franche-Comté: attempt to rank the risk of nosocomial infection.

The aim of this study was to rank the risk of nosocomial infection (NI) according to patient type by analysing the results of annual prevalence studies carried out in Franche-Comté from 2001 to 2004. Patients (N=14,905) were divided into four categories according to the number of endogenous risk factors (age, immunodepression, MacCabe score). The overall prevalence of infection was 6.1% and varied according to the category of patient from 1.93% (no risk factors) to 15.2% (three risk factors). The frequencies of NI related to an invasive procedure and to cross-contamination with multi-drug-resistant (MDR) bacteria were 30.9% and 12.3%, respectively; these percentages did not depend on the type of patient. The prevalence of NI decreased over time for patients with two or three risk factors, but was stable for patients with no risk factors. More than 40% of NIs were potentially avoidable (related to invasive procedures or involving cross-transmission of an MDR bacterium) regardless of the category of patient. This study suggests that at least 30% of NIs could be avoided.